The present invention is related to a stepping type expansion bolt extracting gun and, more particularly to a labor-saving extracting gun which comprises a gun barrel shifting mechanism and an arresting and releasing mechanism.
An expansion bolt is used to be punched in a pre-drilled hole on a wall to provide a support for hanging or fixation of an article. In contrary to regular iron or steel nails, one must drill a hole in advance for an expansion bolt to insert the bolt therein. When an expansion bolt is punched or inserted into the pre-drilled hole, the live spindle of the expansion is extracted to let the middle portion of the expansion bolt protrude outward inside the hole. By means of the live spindle extracting process, the expansion bolt is firmly secured to the wall. Regularly, there are two kinds of expansion bolts available in the market. One is a "push-in type" expansion bolt of which the live spindle must be punched in the pre-drilled hole by a hammer or other suitable tools to force the middle portion of the expansion bolt to protrude outward. The other is an "extracting type" expansion bolt of which the live spindle must be extracted by an extracting tool or the so called expansion bolt extracting gun, to let the live spindle of the expansion bolt be extracted outward so as to further let the middle portion of the bolt protrude outward. The present invention is an improvement in the convention expansion bolt extracting gun.
The expansion bolt extracting gun of the prior art, as illustrated in FIGS. 1 and 2 is similar to a pliers or a shearing tool. The gun is mainly comprised of a fixed handle (1) and a movable handle (2) with a bolt provided to fix both fixed and movable handles together. A movable hollow rod (3) is pivotally connected with the movable handle (2) at the top by means of a bolt (102). A bushing (5) is fixedly attached to the fixed handle (1) at the upper end for the front end of the said movable hollow rod (3). The bushing (5) is arranged to provide a cutting at the front (501) such that the protruding portion (61) of expansion bolt (6) is stopped at the cutting (501) when in operation to extract the live spindle (62). The movable hollow rod (3) is also arranged to provide as cutting (301) at the front to retain the head (63) of the live spindle (62) thereinside. When the movable handle (2) is forced to move toward the fixed handle (1), the live spindle (62) is driven by the movable hollow rod (3) to move outward, so as to let the central expansion portion (64) of the expansion bolt (6) protrude outwardly and to let the expansion bolt be firmly fixed in the hole (as shown in FIG. 2). The structure of the prior art, as above described, is indeed very simple. While in operation, the movable handle (2) is shifted forward to drive the movable hollow rod (3) to move backward. Since the movable handle is connected with the fixed handle by means of a single bolt (101), the shifting of the movable hollow rod (3) is not very stable, and the friction force of the movable hollow rod (3) against the bushing (5) is increased. Further, in the prior art there is no releasing mechanism provided. Therefore, a strong force must be applied at certain times, to drive the movable handle to move toward in the fixed handle.
In view of the inconveniences and drawbacks, a stepping type and labor-saving expansion bolt extracting gun is thus created to provide for better performance.